Once riding a 4-0 record and the best ERA in baseball, Toronto's Mark Buehrle hopes to recapture the formula that led to his outstanding start after an ugly performance in his last outing.

The Blue Jays may need another gem from the veteran following an injury to their leading hitter.

With Melky Cabrera's status uncertain, Buehrle will try to prevent the Kansas City Royals from completing their first three-game sweep of the Blue Jays in almost 21 years Thursday night.

After posting a major league-best 0.64 ERA over his first four starts, Buehrle (4-1, 2.16 ERA) had an opportunity to become the first Toronto hurler to start a season with five straight victories.

But the left-hander allowed 12 hits and seven runs over 5 1-3 innings Friday in an 8-1 home loss to the Red Sox. He gave up more earned runs in Boston's four-run second inning than he had in his first four starts combined.

"I wasn't hitting my spots as good as I was in the past," he said. "And when I did, they got some base hits. But overall, too many strikes in the middle of the zone."

Buehrle, who has allowed one run over 22 2-3 innings in three road starts, looks to bounce back at Kansas City (14-12). However, he's 1-3 with a 6.16 ERA in his last five starts at Kauffman Stadium dating to his time with the Chicago White Sox.

Toronto (12-15) also could have a big hole in its lineup after Cabrera left Wednesday's 4-2 loss when he was hit in the left shin by a pitch in the sixth inning. X-rays taken came back negative and a team spokesman said he was day to day.

Cabrera, who hit a career-high 18 homers while playing for the Royals in 2011, leads the Blue Jays with a .342 average. Toronto was already missing Brett Lawrie, who is day to day with a sore back.

After totaling 20 runs in their previous three, the Blue Jays managed seven hits and went 2 for 14 with runners in scoring position en route to their sixth loss in seven games.

Kansas City's Eric Hosmer had two hits and two RBIs Wednesday, while Alcides Escobar's two-run double broke a 2-all tie in the seventh inning. The Royals won the opener 10-7 behind a six-run eighth.

Now they'll turn to Jeremy Guthrie (2-1, 4.22) as they try to win their fourth in a row and sweep the Blue Jays in a series of three or more games for the first time since July 1993.

Guthrie gave up two runs in the first inning Saturday and none over the next six in a 3-2, 10-inning loss at Baltimore. With runners on first and third and one out in the seventh, he coaxed the Orioles into a double-play to keep the game tied.

"He settled down unbelievably," manager Ned Yost said. "He did a great job of pitching out of a jam in the seventh."

The right-hander looks to continue his recent success versus Toronto after going 1-0 with a 1.44 ERA in his last four starts dating to his time with Baltimore.

Juan Francisco homered in two of his three at-bats when facing Guthrie in 2013, though Cabrera and Jose Bautista are a combined 7 for 34 with no homers since 2010.

Bautista, who has reached base in all 27 games, had 30 walks in April to match Fred McGriff's single-month club record.